After several revelations of Fox’s blatant bias, the rest of the corporate media may finally be catching on.

On Friday, the Los Angeles Times broke a taboo of sorts among mainstream news organizations by urging Fox News to “crack down on… partisanship in its news ranks” or ”stop pretending to be an objective news source.”

The editorial was prompted by the leak of an internal Fox News memo ordering its “reporters” to “refrain from asserting that the planet has warmed (or cooled) in any given period without IMMEDIATELY pointing out that such theories are based upon data that critics have called into question.” The memo was sent by Bill Sammon, Fox News’ Washington managing editor, in 2009 and released by Media Matters last week.

The Times noted that “such data aren’t in serious dispute among climate scientists.”

The way the data are interpreted can vary; it’s legitimate for climate skeptics to reach conclusions that contradict mainstream theories. But only a crank would deny the underlying temperature data that show the Earth getting warmer — records compiled by independent stations around the world, combined with satellite measurements and confirmed by observations of rising sea levels, vanishing glaciers and other inputs — because to do so is to deny material and measurable facts. Instructing reporters to treat such facts as controversial is like telling them to question the laws of gravity when discussing plane crashes. The only reason for doing it is to further a partisan agenda, in this case an attempt to cast doubt on climate science in order to fend off government efforts to limit greenhouse gases.

It’s refreshing to see a leading news outlet abandon the premise that Fox is a “fair and balanced” news organization during the day, and shows its conservative slant only in its evening opinion shows. The Times editorial board noted that mainstream reporters had shrugged off an earlier memo directing Fox personnel to refer to the “public option” as a “government option” during the health-care reform debate because the phase tested poorly among viewers.

The establishment media had also largely ignored internal memos obtained by the Huffington Post after Democrats won control of both chambers of Congress in 2006, which urged Fox News “reporters,” among other things, to “be on the lookout for any statements from the Iraqi insurgents who must be thrilled at the prospect of a Dem-controlled Congress.” Similar missives had been revealed earlier by film-maker Robert Greenwald in his 2004 documentary, “Outfoxed.” The release of this latest memorandum comes on the heels of a study released last week by the Program on International Policy Attitudes at the University of Maryland which found that Fox News viewers are, in the words of News Corpse’s Mark Howard, “significantly more misinformed than consumers of news from other sources.” The study also found that greater exposure to Fox News increases viewers’ misinformation. So, as Howard noted, “the more you watch, the less you know.”

Also last week, the non-partisan watchdog Politifact awarded its “Lie of the Year” award to the claim that the health-care bill passed by Congress last year represented a “government take-over” – a lie that Media Matters demonstrated to have been “repeatedly promoted” on the network’s “news” programs. Last year, the award went to the lie that the health-care reforms would lead to “death panels,” a falsehood also advanced repeatedly on the self-proclaimed news network.

It’s refreshing to see a major news outlet give up the chummy pretense of collegiality and call Fox out for what it is: a 24-hour propaganda operation for the Republican Party. Maybe other mainstream outlets will now follow suit, or at least stop uncritically repeating Fox’s spin.